The custom rules concerning the possibilty resp. prohibition of marriage for members of certain tribe of australian aborigenes are mathematically formulated. This is done 1) in the terms of groups theory and 2) by defining an algebraic operation on the set of groups formed by the members of the tribe a) in the form of a table and b) in the axiomatic way.
 Danielsson, Bengt: Bumerang. Orbis, Praha 1964.